The present invention relates to a portable electric tool having a locking mechanism for adjustably positioning opposing housing sections of the screwdriver.
Portable electric tools, including portable electric screwdrivers, are produced in a variety of different types and configurations. Portable electric screwdrivers commonly comprise a single tubular housing having a chuck assembly mounted at one end and a handle portion at the opposite end. An electric motor is provided in the housing to rotatably drive the chuck assembly. One or more batteries disposed in the handle portion supply power to the motor. This single housing arrangement is capable of performing a variety of tasks, but has limited usefulness in work areas with restricted space.
An alternative arrangement for a portable electric screwdriver is to provide an elongate housing having multiple sections interconnected at a pivot joint. A hingedly connected two-part housing is generally shiftable between an inline stick configuration and a L-shaped configuration to accomplish a variety of tasks in a confined work area. Current pivoting arrangements for screwdrivers use complex structural designs to interconnect the multiple sections of the housing. These various assemblies comprise a multiple section housing interconnected by a fastener at an adjustable joint and a retractable cover which telescopes internally of the housing. The retractable cover is pivotally connected to a separate portion of the housing to limit inadvertent rotation of the housing portions. This adjustable joint assembly, which requires specifically toleranced parts, are problematic because the molded parts may bind during assembly, restricting the rotation of the joint assembly.
It is the goal of the present invention to provide a portable electric screwdriver having a simple, low cost locking mechanism for selectively positioning multiple sections of an elongate housing. Further, it is the goal of the present invention to provide a portable electric screwdriver having a adjustable joint system using a locking mechanism which is strong, reliable and simple to operate.
Accordingly, a portable electric tool is disclosed comprising an elongate housing having a first housing member and a second housing member pivotally connected about a pivot axis to the first housing member along a common mating plane. A channel spaced apart from the pivot axis is formed adjacent a proximal end of the first housing member and is alignable with one of a plurality of apertures formed through a proximal end of the second housing member to form a passage therebetween. Each of the plurality of apertures corresponds to a locking position for the first housing member relative to the second housing member.
A power source is disposed within an inner periphery of the second housing member of the portable electric tool housing. A drive motor is mounted to the inner periphery of the first housing member and is electrically connected to the power source. A chuck assembly adapted to receive a tool bit is mounted to the distal end of the first housing member adjacent the drive motor. The chuck assembly is operatively connected to and rotatably driven by the drive motor. A switch disposed on the outer periphery of the second housing member activates the motor.
A locking mechanism for adjustably positioning the first housing member relative to the second housing member between a first position and at least one second position is provided adjacent the pivot axis of the housing. The locking mechanism includes a spring disposed within the channel in the first housing member, a pin biased against the spring shiftable between a locked position and an unlocked position and a locking member disposed on the second housing member. The pin is biased upward in the passage by the spring to extend through the common mating plane and passage to lock the first housing member of the tool relative to the second housing member. At least one projection extends from the locking member into the plurality of apertures to selectively position the pin in the passage between the first and second housing members relative to the common mating plane.
The locking mechanism is selectively positionable to allow the first housing member of the portable electric tool to rotate relative to the second housing member between a first position and at least one second position. The at least one projection of the locking member engages an upper end of pin to position the upper end of the pin between the locked position and the unlocked position. In the locked position, the spring biases pin through the common mating plane into position between one of the plurality of apertures and the channel to secure the first housing member relative to the second housing member. In the unlocked position, the locking member engages the upper end of the pin, translating the pin downward in the passage against the spring. The first housing member is freely rotatable about the pivot axis when the upper end of the pin extends below the common mating plane such that the pin cooperates only with the channel in the first housing member.